When preparing a joint, i.e. joining two or more structures by means of an adhesive, using a liquid adhesive, such as a glue, it may be difficult to achieve a notch free front line surface of the adhesive bond line, wherein the front line surface is the interface between the adhesive and a surrounding medium, the interface extending between the structures from one structure to the other structure at an end of the joint. This is often due to the liquid adhesive spilling outward from the joint, forming a convex front of the bond line, i.e. a bond line front bulging outward from the bulk of adhesive in the joint and into the medium surrounding the joint such as air. If such spilling occur, notches are likely to form at the interface between the adhesive and each of the structures joined by the adhesive at the bond line front where sharp corners are formed. Notches are usually disadvantageous in a bond line front, since they may weaken the joint.
The problem with notches is specifically pronounced with respect to joints of wind turbines, and especially of wind turbine rotor blades, which are subjected to much stress over long periods of time. Wind turbine blades may be over 40 meters long and have a considerable weight, and must be able to withstand the strong and changing forces exerted by the wind for many years. As there is a need for ever larger blades to be provided to the market, the requirements for joints within the blades to be able to withstand even more stress are ever growing.